Foursquare checkins used to show a user's first name and last
initial, but beginning January 28, 2013, checkins will publicly
display a user's full name.

Additionally, venue owners wanting to take a closer look at
checkins will have access to "more of those recent
check-ins, instead of just three hours worth." There's no
specification on how far back they'll be able to look.

Showing people's full names is bound to stir up some
grumbling among the user base, but FourSquare points out that
there's an easy fix if you don't like it – you can change your
name in your account settings.